1. Field of the Invention
The present invention relates to coating compositions, particularly high solids coating compositions, comprising diluents.
2. Brief Description of the Prior Art
As is known in the art, one of the aims of coating formulators is to eliminate, or reduce to a minimum, the use of organic solvents as aids to film formation or application. Two distinct approaches to these problems have been used. First, water has been used as the solvent, or carrier, for the polymer; and second, the components of the polymer system have been chosen so that they all--or nearly all--have film-forming potential. In this text, coating systems prepared by the second approach which are generally referred to as high solids systems are of a particular interest.
Some of the advantages of these high solids systems are reduced atmospheric pollution, increased film build with a consequent reduction in volume change and stress development during film formation, simplification of painting operations with respect to the number of coats necessary, and economic gains related to the elimination of volatile expensive solvents.
Elimination of solvents from the coating systems ordinarily causes application problems. To avoid these problems, diluents, particularly reactive diluents, are used in high solids systems to aid the application thereof. By definition, reactive diluents are non-volatile organic liquids which contribute to the viscosity reduction of a coating binder (act as an ordinary solvent) but are also capable of reacting with a crosslinker to become part of a crosslinked coating composition. The extent to which the viscosity is reduced depends on the effectiveness of the diluent.
The present invention provides novel reactive diluents which impart desirable properties to films formed from high solids compositions.